Reverse DNS (PTR Record)
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Reverse DNS lookup maps an [[ip-address|IP address]] back to a domain name using PTR records. It's the opposite of a standard [[dns|DNS]] lookup. Reverse DNS is commonly used for email server verification — many mail servers reject messages from IPs without valid PTR records.
Example
Mail servers check that the IP 203.0.113.1 has a PTR record matching mail.example.com before accepting email from it.
Referenced in Guides
DNS Configuration